The Trix is a trio of witches, and the main antagonists of the show. They consist of three witches who are also sisters and they descend from the Ancestral Witches, the most powerful and evil of all witches to have ever existed. They do what they are good at: fighting and pairing up with the enemies. The Trix call each other "sisters" and it is assumed that they are indeed really biological sisters, as the concept of witch covens was never be the Trix, therefore acknowledging them as siblings. In "Twinning With The Witches", Griffin tells the Winx that Witches never work in groups as they always tend to betray each other, thus ruling out the possibility of Witch covens existing in the Winx Club universe. Despite this, they use a convergence in "The Fall of Tritannus". Considering the unusual solidarity among them, the fact that all three of them claim descent from the Ancestral Witches, and that they, along with the Ancestral Witches, are the only Witches known to have worked in groups, it is assumed that they are indeed biological sisters. This is confirmed in "The Problems of Love" when Stormy yells, "We're your sisters!"